Method of tank construction



July 10, 1934. E. E. DILJMAN METHOD oF TANK coNsTRcTIoN Filed Jan. 26A.1935 5 Sheets-Sheet 2 INVENTOR.

rlllllllllllllllill Ill ATTORNEY.

July l0, 1934. v E. E. DILLMAN' METHOD OF TANK CONSTRUCTION 5Sheets-Sheet 3 Filed Jan. 26,- 1953 INVENTOR. f///z/Y/Wff,

BY v

ATTORNEY.

JUIY 10, 1934- E. E.VD1LLMAN I 1,965,736

METHOD OF TANK CONSTRUCTION Filed Jan. 26. 1933 5 Sheets-Sheet 4 Julyl0, 1934.

y E. E. DILLMAN METHOD OF TANK CONSTRUCTION Filed Jan. 26. 1933 5Sheets-Sheet 5 11lIrllllllllllllllllllllllh ATTORNEY.

Patented July 1o,` 1934 UNITED STA-TES PATENT OFFICE 7 Claims. (Cl.25J-148.2)

This invention relates to the construction of welded metal containers,such as`oil tanks, water tanks or containers of this nature for any subiment of the plates or members of a tank can be` controlled during thewelding of the tank, and to prevent them from assuming a curved shape.

Another objectof the improved methodV and means is to maintain theplates in contact at all times and in their assembled relations and toovercome the inherent shrinkage of a welded container, resulting in asymmetrical tank.

A further object of the method is that a bottom angle may be used inconstructing a tank or container by preventing the stressing of thebottom angle during the welding method. Other important objects will beapparent hereinafter. The invention may be readilyy understood from aperusal of the following detailed description, taken in connection withthe accompanying drawings', forming a part of this specification, and inthe drawings:

Figure 1 is a side elevational view of a welded tank constructed inaccordance with the improved means and method. l

Figure 2 is a plan view of a tank bottom including the bottom anglemember of the tank.

Figure 3 is a vertical sectional view through the tank bottom, bottomangle member and a portion of the iirst ring or assemblage of plates,the

view being in broken formation for convenience of illustration.

Figure 4 is a View similar to Figure 3, but showing the tank parts inassembledposition `before welding, Figure 3 illustrating the tank afterwelding with consequent reduction of its diameter.

Figures 5, 6 and 'T are fragmentary detail sectional views respectivelyof modifications of overlapped construction susceptible of 'use with themethod.

Figure 8 is aside elevationalview `in part of a tank wall, bottom anglemember and `the tank bottom, after welding, or a developed bottom angleand first course in welded position.

showing the parts prior to welding, with the use `of devices forclamping the member in assembled position.

Figure lois a cross-sectional view on line 10-10 of Figure 8, and Figure11 is a cross-sectional view 00 on line 11, Figure 9. y

Figure 12 is a detail view of a clamping device for holding the .platesin assembled position during the welding, the device being related butdiierent from the device shown in Figure, 11.

`Figure 13 is an elevational view of the first course of shell plates inassembled position with developed bottom angle, before welding.

Figure 14 is a similar view to that of Figure 13, but showing the platesafter the welding of 70. the horizontal seams.

Figure 15 is a view similar to Figures 13 and 14, but illustratingdeveloped bottom angle and rst and second course -of shell plates afterwelding. 75

Figures 16 to 19, inclusive, represent diagrammatically the action andresult of expansion forces and movements thereof.

Figure 20 illustrates in part the plan view of a tank bottom and itsangle member, Figure 21 8G being a cross-sectional view on line 21-21 ofFigure 20, these views for the purpose of illustrating faultyconstruction to be overcome.

Figures '22 and y23 are vertical sectional views of a tank bottom, anglemember and the rst course of shell plates in position before welding,the latter (Figure 23) showing the completed bottom with the bucklingremoved.

Figures 24 to 29 inclusive are shown to illustrate tank construction notemployed in this method and to make clear the purpose of thisinvention,-Figures 24, 25 and 26 .representing plan views in part ofaltank bottom and part of the tank shell', and Figures 27, 28 and 29being crosssectional views of Figures 24., 25 and 26, respec- 95 tively.

Figure 30 is a sectional view of a tank which has resulted from faultyconstruction, causing abnormal reduction of 'capacity and lack ofsymmetry-the view being shown for the purpose of Y making clear theimproved method and means to be now more particularly described indetail.

In Figure 1 is shown a tank constructed in accordance with the improvedmethod and in which the seams are overlapped or in which these seams`are a. modification of overlapped construction such as is shown inFigures 5, 6 and '7. Figure i shows the construction ofv a tankascarried outl in the improved method and thetrue relation of the lplates 2 to each other in order thatthe tank or 110 l angle as at 3.

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. appear will b e in diiferent and symmetrical, must be vis caused bythe welding of container will be symmetrical in shape. The courses,rings, or sections of a tank, to be thus in a true vertical plane andthe 'top of eachring, course or section, each horizontal seam, talplane, or in the planes as required bythe shape and form of thecontainer. To obtain this result and at the same time produceastructurally sound tank is the object and purpose of the method andmeans herein described.

In constructing the improved tank and as shown in Figure 2 the bottomplates are held in position by light tack welds 3, after being properlyassembled with the bottom angle 4, also similarly tack welded to thebottom plates 2. The only `continuous welding or strength welding doneon these members at this time is the welding of the overlapped seamsthat fall under the bottom To these seams there is'no access for weldingafter the bottom angle is placed inv position. This lplan view thusshows the relative position -of these members in assembled relationbefore any strength welding takes place. Figure 4 shows therelativeposition of the plates 2 which constitute the shell of the tank inassembled position prior to welding, while Figure 3 illustrates theparts after welding, the dotted lines and arrow-heads indicatingdiameter before and after the welding has been done'.

As previously stated, to provide a symmetrical tank, the walls or sidesmust be in a vertical plane change in diameter, of the rst ring, course,or section, must be controlled. A certain portion of this shrinkagecomes fromthe welding of the bottom plates to each other. This isrelatively small, however, as the major portion of the shrinkage thebottom angle to the bottom plates. l f

The welding of a circular section, such as abottom angle or ring, to aflat plate, such as the bot-'- tom of a container such as shown inFigures 3 and 4 causes a contraction oi the diameter of this circularsection. It the that is the equivalent of the change in bottom is a.complete unit, of a solid plate, the result diameter referred to 'abovebottom will rise up from the foundation at some points, since there ismorev area of plate in' the bottom than required by the smaller diameterdepends on conditions such as heat of the welding arc and thicknessofthe respective members, the exact amount of shrinkage cannot bedetermined before welding takes place. The procedure and methods oi'welding andassembly must compensate for this unknown factor. x

Assuming that the bottom of the tank is -in one piece, the con bottomafter Welding is: the bottom plates will not rest evenly on thefoundations after the welding takes placeJ The strength of the bottom towithstand a contractive -stress applied at the outside edge of thediameter tive stress, since the bottom is in one integral unit. As thisplate is circular in shape, the buckles-that varied positions. In somecases they will be under the bottom angle andin" others towards thecenter of the bottom.- Yr"*'*As fa-result.oi?

bottom under the this buckling condition of the bottom anglefthetopvesige B 01 dure is carried out.

of the first ring, course or section,

=welded from the inside of the of the ring. Since this change `vaurasassumed that a -necting the first ring to the bottom angle was ing'ofthe members by each other as` the circumthe bottom angle 4 would not liein a horizontal plane, and the upstanding leg- 'I of the angle would bein or-outside of a vertical plane as indicated by the dotted lines andarrow-head in Figure 2l. This condition can only result in a tank thatis not symmetrical and in which buckles will appear in the shell.

To overcome the condition shown in Figures 20 and 2l, which is caused bythe buckling ofthe bottom plates, the following method and proce- InFigure 2 is shown the bot- Y' tom, composed of the plates 2 and thebottom angle 4 in place in the assembled position-. These members areheldin such positionby vthe light tack welds 3 as previously stated. Tothe bottom angle 4 is attached the first ring or section, that is theplates 2 in Figure 4. The first continuousweld the weld connecting thebottom angle4to the bottom plates 2. This is shown in detail in Figurel0. Attention is calledA to the. `fact that all plates in the bottom andthe bottom angles are maintained in position by light tack welds 3.' Itwill beassumed that a satisfactory method of attaching the first ring orcourse to the bottom angle is used. This ring is attached before theweld are particularly weak against a contractive force applied at theextreme edge, the vertical force A that is, weight,- will hold the angleon the foundation1 ,This will be clear from Figure 22, the first ringbeing indicated at 8. This arrangement forges the buckles 9 to appear inthe bottom away from the edges. At the completion of the welding o'f thebottom' angle to the bottom plate, all contraction 'from 110 thiswelding has taken place and'has resulted in buckles in the bottom.

The bottom longitudinaf seams 10 are now bottom angle to the center ofthe'bottom. Y As these seams are welded, 115 the light tack welds 3break?, or are mechanically broken, which allows each plate to shiftslightly, thus compensating for the change in diameter. This shiftingcan readily take place, as the crossseams 11 are not welded untilthelongitudinal 120 seams 10are welded. This method results in a atbottom 12 resting evenly on the grade, and having the top edge of thebottom angle in a horizontal piane and the upstanding leg. thereof A'Iin a vertical plane as show`n in Figure 23.

In the above description of the method used to procure a flat, ylevelbottom and bottom angle, it

satisfactory means .of conused. A perusal of Figures 8 and 9 will showthe 130 rst and primary condition to be met if a safe and structurallysound tank is to be secured. Figure!) shows an elevational view in partof the first ring of a tank attached to the bottom angle in an assembledand developed position. Figure 135 8 shows that the bottom and thebottom angle have been welded. This is a developed section and has thechange in circumference as the result of this welding. As the diameterof the bottom becomes smaller, the circumference becomes smaller.

Let it be assumed that the first ring is retained f -in position by somemeans that prevents a lateral movement-of the plates. that is, preventsthe slidference .becomes smaller. This condition r`would be secured ifholes were punched in the angle and `plates so that 4these holes wouldmatch bolts or rivets used'to hold the plates inposition. See Figure 24.'I'he bolts are indicated-at 13 and 8 1 50 10o i 3 is made, see Figure10. As thebottom plates represents the rst ring. This arrangement wouldresult in the condition shown in Figure or in Figure 26,l depending uponwhich type of bottom angle construction is used. If the constructionshown in Figure 25 is used, the plates must buckle between the bolt orrivet holes or h old the bottom angle to the assembled diameter of thebottom ring. If the construction shown in Figure 26 is used, theplatesmlist buckle between the plates, as shown in the drawings. Theposition the plates -will take depends upon the strength to withstandbuckling that the first ring plates will have. As the plates must buckleagainst the arch of the plates/and if theplates are relatively thick andthe holes relatively close together, the condition shown in Figure 24will probably maintain. If the condition is as shown in Figure 2501Figure 26, buckles will appear on the first ring and the ring will nothave the plates in vertical plane, and the top edge of the plates willnot be in ahorizontal plane. In all cases in which the bottom angle isoutside of the first ring, the symmetry of the tank will not beaffected, but the safety of the structure would be affected. Since thetank must maintain its assembled diameter, and as it is assumed that thefirst ring is rigidly fixed to the bottom angle, stresses will be set upin the bottom angle. The bottom angle will tend to contract as it iswelded. It must con,- tract against the first ring, which is fixed indiameter because of the bolts 13.' The resistance of the rst ring tocontraction will cause the-bottom angle to maintain its position asassembled. Since this contraction of the bottom angle does not takeplace, a stress must be set up, either `in bottom angle Weld or thebottom angle. If this stress is in the bottom angle. it will be atensile stress. As the stress in the bottom angle from the loads in thetank are tensile stresses, the -net result of the stress in the bottomangle from welding is to increase the stresses by that amount.Consequently, greater stresses are built up than called for in thedesign.

That this has been the case and the result of such design has beenestablished by bottom angle failures where welded bottoms have beenattached tof riveted shells. In the case of riveted shells and weldedbottoms, this condition has been accentuated to a maximum degree, as theshell welded to the bottom plates.

contact.

diameter must be constant and the d'ameter of the bottom and bottomangle after Welding must be restrained to this degree.

To overcome the condition described above, a clamp device is used thatwill hold the plates temporarily in the correct position.A Any clamp de#vice used must hold the members in contact through friction so that themembers can slide by each other to compensate for the smaller dameterafter welding and the smaller circumference. One type of such clampdevice is shown in Figure 11.

It is imperative that the members be free to move by each other in orderto compensate for the inherentl change in diameter due to thecontraetion of the bottom angle or section when it is The clamp devicemust not allow the members to get away from the assembled position andmust hold the members in This result is secured through frictionalcontact and as there are no means of connection through the members,they can slide by i each other as contraction takes place.

frictional force exerted by the clamp can be re- Since the contractionof the -diameter and ring, stresses cannot be builtA up in any of thewelds or members. The members will be constantly in contact and willremain in their assembled relation.

Reference to'the drawings, Figures 13 to 15 inclusive, illustratesanother necessary attribute of a fitting up device. Figure 13 shows adeveloped elevation of the first ring of a tank before welding. Theplates 2 in this view are held in position byA a device that does notrest -against the edge of the horizontal seam, see Figure 1,2, as doesthe device shown in Figure 11. This device consists of an angular body18 and a screw bolt 19 for frlctionally holding the bottom angle and thefirst ring together. Or let itV be assumed that any device maybe workedout that meets the requirements of the conditions described, and doesnot rest against the horizontal seam, either on the inside of the shellor Wall or on the outside. When the horizontal seam is Welded there willbe a movement of the plate that is being welded, which will.

cause the plates to become curved as at 20, Figures 14 and l5, on thelongitudinal edges. Figure 15 shows the same condition in the developedsection of rings one above the other, or sections, of. the plates 2. Bya ringis meant a circular row of plates 2. All other rings would besimilarly conditioned. The result of this movement would cause theplates toshorten and result in the top of the rings falling inside ofthe vertical plane. The resultf of this condition would be that as thetopof each ring fell inside of the vertical plane, -the finished tankwould assume a shape similar to that shown in Figure 30. This form oftank would be inipractical because of the reduction in capacity, itslack of Asymmetry and the difficulty encountered in placing thesupporting steel fol' the roof;

This curving'of the longitudinal edges of the plate is caused by thecontraction of the plates along the edgesbeing welded. The heatingcaused by the welding tends to make the plate. 4

expand; but since this heat is localized at the point of welding and isgradually diffused into the colder portionsof the plate, this expansiontakesplace against cold metal. This cold metal is very resistant todeformation. .As the metal at the point of welding is in a molten state,this expansion causes the vhot metal, which is much less resistant to agiven force, to deform and the molecules to become closer together. Theedge ofI the plate or member becomes shorter and causes the plate totake a curved position. This condition is inherent in theweldingprocess.l

In Figure 16 is shown a portion of one plate and a portion ofthe bottoniangle removed from thevshell or wall of a tank. Welding-has taken placelat the point A*. Figure 17 shows diagrammatically the expansion forcescaused by the welding -resolved into vertical and horizontal forces.Similarly to Figure 17, Figure 18 shows the resultant movement of theseforces. As the bottom angle is restrained by the foundation, all themovement will be in the plate, resulting in a downward and horizontalmovement, as shown by the resultant. This movement will result in adeformation of the plate.

If a force is vintroduced that will oppose the vertical resultant R`V inFigure 18, the downward movement would be restrained and all movementwould be in ahorizontal direction. Figure 19 shows graphically theintroduction of such a forcent the point A. The bottom angle is reyicthe members be allowed tion. Any other ring or course after the lowerhorizontal seam is Welded would also be restrained from a verticalmovement, as any force tending to cause such movement would betransmitted to the foundations through the lower rings and bottom angle.This force FC as shown in Figure 19 requires that any device used be sodesigned and placed that any vertical force will be transmitted tomembers that are ilxed in position.

It becomes apparent that tack welding the plates together would satisfythe condition that a vertical movement be restrained. This method oflerection would not satisfythe condition that to slide by each other aswelding takes place. A shown in Figures 25 and the contraction due tocondition similar to that 26 would result if such a a condition wouldjeopardize the structural integrity of thetank and must be avoided. f

A device, to be effective, must hold theplates together by friction, andthis frictional` force must be vreadily adjustable so that a horizontalmovement, 'vertical movement or any movement as-required by the shapeand type of container can readily take place.. This movement willcompensate ior the change in diameter that takes place -when thecontainer is welded. A device must` rest on the'next lower member or beso designed that -a verticalmovement of the memb er being welded isrestrained, and thus prevent a curvature of the member or plate beingwelded. In order to make effective vthe methods and devicesdescribed-.the vertical seams are not we1d.

eduntil all thehorizontal seams are welded.

In welding the Avertical seams last, any movement e of the members willbe restrained to a horizontal A. plates when -the curb. -r'nem to thebottom movement, which will be compensated for by; the open, unjoinedeseams. -The welded. horizontal seams will restrain the vertical seams tothe assembled position and .insure a symmetrical tank.

'I'lie methodherein described and illustrated when used with the generaltype of `clamping device shown in Figure 12 will result in a sym-'metrical and structurally, sound container. 'I'he invention is intendedto embrace variations in the method of. lap welding of tanks as'statedand the clamping means may also. be alt-erated and mod ied to an extentin keeping with the appended claims, *a

What is claimed asnew isz. 1. A method oi' constructing amulti-platetank which comprises assembling plates in over-lappedposition to form a bottom,

attaching a ring or section of wall platesto y the bottom angle iron,permanently welding the bottom angle iron th permanently plates. A

2. A method of makinga multi-plate structure,

vwhich comprises assembling plates in rows and in overlapped position atall meeting edges, each temporarily row comprising a pluralitywf plates,uniting the .plates by light tack welds, placing a curb member on `theplates, securing the curb memberagainst distortion'by the buckling oftherfshrinks in diam'- method was used. Such,v

plates, permanently welding ilrst.` Ilongitudinal seams of the bottom-plates, then ,f welding the cross .seams ot saidc 1,9ers,'z'seAstrained from a vertical movement by the funda- 3. A method ofconstructing a multipl'ate tank accordingto c1aim.6 ,which consists. ofadding additional'rings or sections to the ilrst ring or' sectionattached tothe curb member or bottom angler'lron by means of' -frictionclamp members vrto permit lateral movement of the plates when welded.together and to prevent the plates from assuming a curvature, andwelding iirst the longitudinal seams ofthe side plates, then welding thecross'seams of said plates.

4. A method of constructing a multi-plate tank which4 consists ofassembling bottom plates in over-lapped relation, tack welding`the`p1ates,

placing permanent welding in the seams of thel plates; which wi1l comeunder a curb member, seating a curb'member with attached first ring sideplates on the bottom plates, permanently welding the/curb member to thebottom plates,

Welding the longitudinal seams, and then the cross seams of the bottomplates; then using frictional means for-holding successive side wallsections of plates to said rst ring of plates, to prevent verticalmovement of the member being welded to avoid curvature of the sideplates, and then welding rst the horizontal seams and then the verticalseams to form the completed tank.

"5. A method of constructing a multi-plate tank which comprisesattaching by means of frictional clamps the plates of the Side wallSections or rings to a lcurb angle on theassembledbottom plates of thetank,pror to the Welding of said bottom plates, then similarly and bymeans oi' i'rictional lclamps attaching the plates of successive sidewall sections to the next lower adjacent side wall section, said clampsbeing adjustable to permit adjustment of the frictional force holdingthe plates in contact, in order that the plates, may adjust themselvesto the nal dimensions of the tank after welding.

' 6. A method of making a hollow sheet metal structure which comprisesattaching by means of frictional clamps the plates of a side wallsectionor ringtoa lower section or ring, then similarly.an'd by means offrictional clamps attaching ios successive side wall sections each tothenext lower section, said clamps being adjustable to temporarily unitingthe plates bytack welds, placing a' bottom angle iron on the plates,retaiingthebottom angle -iron` in. position by light tack welds,

permit adjustment of the vfrictional force holding the plates incontact, in order that `the plates may adjust themselves to the ilnaldimensions of the structure after welding.

7. Av method of making va hollow sheet. metal structure vwhich comprisesattaching by means of frictional clamps the plates of a side w'allsection or ring. toa lower section or ring, then similarly and by meansof fritional clamps attaching successive sidewall sections each to thenext lower section, said clamps being adjustable to permit adjustment ofthe frictional force holding that the plates ilnal dimensions Weldingthe cirwelding the cross

